Surgical staple and instrument for holding and implanting the surgical staple

ABSTRACT

A surgical staple insertion system for compressing bone fragments includes a staple and an insertion tool. The staple has first and second legs and an elastically deformable bridge monolithically formed with the first and second legs. In a relaxed configuration, the bridge is curved such that a central region of the bridge is directed away from the first and second legs, and free ends of the first and second legs are positioned closer to one another than are portions of the first and second legs connected to the bridge. The bridge includes engagement portions at each of its first and second end sections that extend away from each other. The insertion tool includes an end defining a cavity configured to receive the engagement portions at the end sections of the bridge to retain the bridge in a deformed configuration with the first and second legs retained parallel to each other.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application is a continuation of U.S. Ser. No. 15/161,124,filed May 20, 2016, which claims benefit of U.S. Provisional PatentApplication Ser. No. 62/164,402, filed on May 20, 2015, and which claimspriority from European Patent Application EP 15168542.7, filed on May20, 2015, the contents of all of which are hereby incorporated byreference in their entireties.

BACKGROUND Field

The present invention relates generally to surgical staples used forcompressing bones or bone fragments. More specifically, the inventionrelates to surgical staples including a first leg for anchoring in afirst bone or bone fragment, a second leg for anchoring in a second boneor bone fragment, and a bridge connecting the first leg and the secondleg. The invention also relates to an instrument for holding andimplanting surgical staples.

Description of Related Art

Surgical staples are used to treat angular deformations, fracturesparticularly with respect to the extremities, subluxation, dislocation,arthritis, or other issues that may occur with regard to bones of thehuman body. The staples are attached to respective bones or bonefragments to fuse the bones or bone fragments together while exerting acompressive force on them. Staples are advantageous over other fusiontechniques such as plates, for example, in view of their compactness andflexibility.

Document U.S. Pat. No. 6,908,467 B2 discloses a distraction device madefrom a nitinol wire which includes an S-curve and bent end regionsprovided with hooks for anchoring in the bony material. When thedistraction device is implanted, a rise of the temperature above thetransfer temperature causes the shape memory material to change from amartensite state to an austenite state. The device is distracted whenthe S-curve assumes an elongated shape in the austenite state. The hooksself-lock in the opposing bone surfaces and the bone sections distract.Due to the superelastic characteristics of Nitinol, the distractionforce remains more constant.

Document U.S. Pat. No. 7,618,441 B2 discloses a bone staple which may bemade of Nitinol. The staple has a bridge and legs extending from cornerjoints adjacent respective end portions of the bridge. The bridge may beslightly arc-shaped whereas the legs extend parallel to each other. Thebridge also slightly extends beyond the corner joints thereby formingstop means or shoulders. The shoulders serve for reinforcing theconnection between the legs and the bridge, and, since the level of theshoulder is lower than the bridge, for preventing the bridges fromentering into contact with the bone. The staple is used to addressconvexity or concaveness of the vertebral column, wherein the shapememory effect of Nitinol is employed to splay the legs of the stapleinserted into respective vertebrae away from each other.

Document GB 2471648 B discloses a staple for bones. The staple may bemade of a shape memory material such as NiTi and has a connectorincluding a ring of curved portions allowed to be distracted and furtherincluding three or four legs arranged parallel to each other.

Document US 2013/0026206 A1 discloses a bone staple which has a bridgeconnecting two legs and which is made from Nitinol. The bridge has anS-shape in a plane perpendicular to that of the legs and the legs areinclined toward each other in a closed configuration. In an openedconfiguration, the legs become parallel.

Document US 2013/0231667 A1 discloses a surgical staple having a middlesection or bridge and side sections or legs which cantilever from endsof the middle section at an angle close to 90°. In a relaxedconfiguration, the middle section is curved within the plane of the sidesections and has an angle of curvature between 15° and 35°. The sidesections extend towards each other in this configuration. Use of Nitinolsuperelastic material is also disclosed therein.

Document US 2014/0277516 A1 discloses a bone staple including a bridgeand legs extending from ends of the bridge. The bridge has a straightshape in a relaxed as well as in a splayed configuration of the legs. Tosplay the legs, the staple is put on a storage block and two tips ofrespective pivoting inserter handles force the side legs into thesplayed configuration at 90° relative to the bridge. The staple is madefrom a super elastic and shape memory material such as Nitinol ASTM2063.

Document US 2014/0358187 A1 discloses a surgical staple and a stapleinsertion device. The staple may be made of Nitinol and has a bridge andlegs extending from ends of the bridge. To achieve a tensionedconfiguration in which the legs are parallel to each other, the stapleis loaded to jaws of the insertion device which may be rotated outwardsby means of a spacer configured to separate the jaws, which adverselyengage the legs of the staple.

SUMMARY

It is an object of the invention to provide a surgical staple and aninsertion holder which improves the process of insertion of the stapleinto bones.

According to an embodiment, a surgical staple for compressing bones orbone fragments includes a first leg and a second leg for anchoring inrespective bones or bone fragments. A bridge connects the first leg andthe second leg. The bridge has a first end section and a second endsection opposite the first end section. The legs extend from therespective end sections.

The bridge is provided to be arc-shaped, or curved in at least a portionthereof, in a relaxed state of the staple (e.g., a state withoutexternal forces acting on the staple). The bridge can assume a straightshape with, for example, a flat bottom surface when the staple isadjusted to an expanded, or opened, state by means of an instrument. Inthe expanded state of the staple, the legs are generally brought into aparallel configuration, which is suitable for insertion into pre-drilledholes in the bones or bone fragments.

The bridge may acquire mechanical energy when the staple is expanded andthe bridge is bent to splay the legs towards a parallel configuration.In other words, the bridge does not only connect the legs but alsocontributes to achieving the expanded state of the legs. Advantageously,when the staple is in the expanded state, the bridge may attain astraight shape with its flat bottom side section, thereby closelyfollowing the surface of the bones or bone fragments involved. As aconsequence, the staple may consume or take up less space within thesoft tissue adjacent the bones or below the skin.

In order to allow the staple and its bridge thus expanded or bentrespectively to be attached to bones or bone fragments, the surgicalstaple according to an embodiment further comprises at least oneengagement portion for engagement by an external instrument or tool. Theengagement portion allows engaging the bridge and maintaining the bridgeat the straight shape. According to some embodiments of the invention,the engagement portion may be for example a recess or a projectionhaving a surface facing or at least inclined towards one or both of thefirst and second legs. In many embodiments of the invention, there areat least two engagement portions provided at the bridge, which allowsengaging the bridge from two sides.

The one or more engagement portions are preferably provided to extend ator adjacent the end section(s) of the bridge. This allows exertion of apulling force onto the end sections by means of an instrument with hightorque via the engagement portions, while a pressing force can beexerted on the top surface in a center section of the bridge in anopposite direction, with the consequence that the bridge bends and thelegs move away from each other into a parallel configuration.

In an embodiment, the at least one engagement portion may also belocated above or on a side of a plane defined by a bottom surface of thebridge opposite the legs when the bridge is straightened. Such plane maycorrespond to a bone surface when the surgical staple is inserted in abone. An advantage thereby arises in that engagement structures of theexternal instrument may engage the at least one engagement portion at aheight level above said plane, such that the legs of the staple can beinserted into pre-drilled holes in the bones or bone fragments until theflat bottom side section of the bridge abuts on the bone surface.

As a result, no parts of the external tool are sandwiched between thebridge and the bone upon attachment of the staple to the bones or bonefragments, such that it is not necessary to remove the tool before thestaple is fully inserted, and then to separately hammer the staplefurther into the holes. Rather, the staple may be fully positioned orinserted in the bones or bone fragments using the external instrumentonly. Hence, the number of steps of insertion is also reduced.

According to a further embodiment, the surgical staple may at leastpartially be made from a shape memory material, in particular Nitinol.The surgical staple can be in its first, relaxed state upon fabricationin the austenitic phase. For easy insertion, the surgical staple can bedeformed into a desired second shape having parallel legs and a straightbridge, for example, as explained above. The staple may be deformed by atransfer instrument or pliers, for example. The deformed surgical staplemay be transferred from the transfer instrument or pliers to a stapleholder. Another option is to use the same pliers for deformation as wellas for inserting the staple into the bone(s).

When inserting the staple into bones of the human body, a so calledsuperelasticity or pseudoelasticity of the shape-memory alloy can beutilized. This allows the staple to exert a compression onto the bonesinvolved after insertion and release of the staple from the stapleholder or pliers. The superelastic deformation of the staple from itsrelaxed shape to its expanded shape involves a phase transformation fromaustenite to martensite in the highly loaded areas of the staple. Theseareas remain under a certain stress after insertion of the staple, andenable the staple to exert a force onto the bones to compress the bones.

In line with the surgical staple described above, there is provided astaple holder according to a further embodiment. The staple holderincludes a face formed with a cavity shaped to receive the bridge of thesurgical staple in an expanded state thereof, wherein the cavity isprovided with at least one engagement structure complementary to andcooperating with respective engagement portions provided at the bridgeof the staple. The cavity thereby provides at least some of the reverseor opposing surface features of the bridge including the engagementportions. As the cavity is adjacent to and opens towards the face of thestaple holder, the bridge may safely be received in the cavity with thelegs and the bottom side section of the bridge being exposed to theoutside of the staple holder, and ready for insertion into one or morebones.

According to a further embodiment, an expansion device is provided thatincludes a transfer portion provided on a boss, which allows displacingor moving of the surgical staple from a first portion of the boss wherethe staple is received in its relaxed state, to a second portion of theboss where the staple assumes the expanded state. The expansion of thestaple may be an elastic deformation or a plastic deformation. Anaccommodation space which accommodates the staple holder is structuredor positioned to allow the bridge to be received or advanced into thecavity of the staple holder when the staple is at the second portion ofthe boss.

BRIEF DESCRIPTION OF THE DRAWINGS

Further aspects and advantages of the invention will be betterunderstood in view of the following description taken in conjunctionwith the accompanying drawings. In the drawings:

FIG. 1a shows a perspective view of a surgical staple according to afirst embodiment in a relaxed state;

FIG. 1b shows a perspective view of the surgical staple according to thefirst embodiment in an expanded state;

FIG. 1c shows a front view of the surgical staple according to the firstembodiment in the relaxed state;

FIG. 1d shows a front view of the surgical staple according to the firstembodiment in an expanded state;

FIG. 2a shows a perspective view of a first embodiment of an instrumentin the form of an expansion device;

FIG. 2b shows a perspective view of an expansion device according to analternative embodiment;

FIG. 3a shows a perspective view of a first embodiment of a stapleholder;

FIG. 3b shows an enlarged view of a cavity of the staple holder of FIG.3 a;

FIG. 4 shows an enlarged perspective view of a surgical staple accordingto the first embodiment first received in the relaxed state on theexpansion device of FIG. 2a , and then received in the staple holder ofFIG. 3a , which is connected to the expansion device, when the staple isadjusted to the expanded state;

FIG. 5a shows a second embodiment of an instrument in the form of pliersreceiving a staple according to the first embodiment;

FIG. 5b shows the pliers expanding the staple according to the firstembodiment;

FIG. 5c shows the pliers attaching the staple according to the firstembodiment to a staple holder similar to the staple holder shown inFIGS. 3a and 3 b;

FIG. 6a shows a plan view of the pliers and staple shown in FIG. 5a ,with the staple being in a relaxed state;

FIG. 6b shows a plan view of the pliers and staple shown in FIG. 5b ,with the staple being expanded;

FIG. 6c shows a plan view of the pliers, staple, and staple holder shownin FIG. 5 b;

FIG. 6d shows a plan view of the pliers, staple, and staple holder shownin FIG. 5 c;

FIG. 7a shows an enlarged perspective view of the staple and a portionof the pliers in FIG. 5 a;

FIG. 7b shows an enlarged perspective view of the staple and portions ofthe pliers and staple holder in FIG. 5 c;

FIG. 8a shows the staple according to the first embodiment in a methodof anchoring the staple in a bone;

FIG. 8b shows a step of engaging engagement portions of the staple witha third embodiment of an instrument;

FIG. 8c shows a step of expanding the staple using the third embodimentof the instrument;

FIG. 8d shows a step of aligning legs of the staple with holespreviously drilled in a bone while the staple is held in an expandedstate by the third embodiment of the instrument;

FIG. 8e shows a step of inserting the legs of the staple into thepre-drilled holes of the bone;

FIG. 8f shows an enlarged and partially transparent perspective view ofthe step depicted in FIG. 8 e;

FIG. 8g shows an enlarged and partially transparent side view of thestep depicted in FIG. 8 e;

FIG. 8h shows an enlarged and partially transparent side view after astep of releasing and removing the third embodiment of the instrumentfrom the staple;

FIG. 9a shows a perspective view of a surgical staple according to asecond embodiment in a relaxed state, the staple having asymmetricallyextending legs;

FIG. 9b shows a perspective view of the surgical staple according to thesecond embodiment in an expanded state;

FIG. 9c shows a front view of the surgical staple according to thesecond embodiment in the relaxed state;

FIG. 9d shows a front view of the surgical staple according to thesecond embodiment in the expanded state;

FIG. 10a shows a perspective view of a surgical staple according to athird embodiment in a relaxed state, the staple having a bridge with aT-shaped profile and engagement portions connected on both sides of thebridge;

FIG. 10b shows a perspective view of the surgical staple according tothe third embodiment in an expanded state;

FIG. 10c shows a front view and a side view of the surgical staple oaccording to the third embodiment in the relaxed state;

FIG. 10d shows a front view and a side view of the surgical stapleaccording to the third embodiment in the expanded state;

FIG. 11a shows a perspective view of a surgical staple i according to afourth embodiment in a relaxed state, the staple having a bridge with aT-shaped profile and engagement portions separated on both sides of thebridge;

FIG. 11b shows a perspective view of the surgical staple according tothe fourth embodiment in an expanded state;

FIG. 11c shows a front view of the surgical staple according to thefourth embodiment in the relaxed state;

FIG. 11d shows a front view of the surgical staple according to thefourth embodiment in the expanded state;

FIG. 12a shows the surgical staple according to the fourth embodiment ina method of anchoring the staple;

FIG. 12b shows a step of engaging the staple with a fourth embodiment ofan instrument;

FIG. 12c shows a step of expanding the staple using the fourthembodiment of the instrument;

FIG. 13a shows a perspective view of a surgical staple according to afifth embodiment in a relaxed state, the staple having a bridge with aT-shaped profile and engagement portions separated on one side of thebridge and connected on the other side of the bridge;

FIG. 13b shows a perspective view of the surgical staple according tothe fifth embodiment in an expanded state;

FIG. 13c shows a front view of the surgical staple according to thefifth embodiment in the relaxed state;

FIG. 13d shows a front view of the surgical staple according to thefifth embodiment in the expanded state;

FIG. 14a shows a perspective view of a surgical staple according to asixth embodiment in a relaxed state, the staple having a bridge with anL-shaped profile;

FIG. 14b shows a perspective view of the surgical staple according tothe sixth embodiment in an expanded state;

FIG. 14c shows a front view and a side view of the surgical stapleaccording to the sixth embodiment in the relaxed state;

FIG. 14d shows a front view and a side view of the surgical stapleaccording to the sixth embodiment in the expanded state;

FIG. 15a shows a perspective view of a surgical staple according to aseventh embodiment in a relaxed state, the staple having a bridge withan L-shaped profile and engagement portions separated from each other onone side of the bridge;

FIG. 15b shows a perspective view of the surgical staple o according tothe seventh embodiment in an expanded state;

FIG. 15c shows a front and side view of the surgical staple according tothe seventh embodiment in the relaxed state;

FIG. 15d shows a front and side view of the surgical staple according tothe seventh embodiment in the expanded state;

FIG. 16a shows a perspective view of a surgical staple according to aneighth embodiment in an expanded state, with inclined engagementportions provided on opposite side walls of a bridge of the staple;

FIG. 16b shows a side view of the surgical staple according to theeighth embodiment in the expanded state;

FIG. 17a shows a perspective view of a surgical staple according to aninth embodiment in an expanded state, with engagement portions formedas recesses at side walls of a bridge of the staple;

FIG. 17b shows a side view of the surgical staple according to the ninthembodiment in the expanded state;

FIG. 18a shows a perspective view of a surgical staple according to atenth embodiment in a relaxed state, the staple having a bridge withextensions and a discontinuous arc-shape;

FIG. 18b shows a perspective view of the surgical staple according tothe tenth embodiment in an expanded state;

FIG. 18c shows a front view of the surgical staple according to thetenth embodiment in the relaxed state;

FIG. 18d shows a front view of the surgical staple according to thetenth embodiment in the expanded state;

FIG. 19a shows a staple according to the first embodiment in a methodfor anchoring the staple;

FIG. 19b shows a step of using a fifth embodiment of an instrument toreceive the staple when the staple is in a relaxed state;

FIG. 19c shows a step of expanding the staple using a pressing member ofthe fifth embodiment of the instrument;

FIG. 20a shows a perspective view of a surgical staple according to aneleventh embodiment in a relaxed state, the staple having a bridge witha T-shaped profile and a convex-shaped engagement portion;

FIG. 20b shows a perspective view of the surgical staple according tothe eleventh embodiment in an expanded state;

FIG. 20c shows a front view of the surgical staple according to theeleventh embodiment in the relaxed state;

FIG. 20d shows a front view of the surgical staple according to theeleventh embodiment in the expanded state;

FIG. 21 shows a perspective view of a sixth embodiment of an instrumentin the form of pliers, in a state of holding an expanded staple of thefirst embodiment, the pliers having an inner screw member to maintainthe expanded state of the staple;

FIG. 22a shows an enlarged view of tip portions of the pliers of FIG. 21in a first step of a method for receiving, expanding, holding, andplacing the surgical staple in a bone;

FIG. 22b shows the pliers and staple of FIG. 22a in a second step of themethod;

FIG. 22c shows the pliers and staple of FIGS. 22a and 22b in a thirdstep of the method;

FIG. 23a shows a perspective view of a seventh embodiment of aninstrument in the form of pliers, in an opened state, the pliers havinga toggle lever;

FIG. 23b shows an enlarged view of a tip portion of the pliers;

FIG. 24a shows an enlarged perspective view of a surgical staple and thetip portion of the pliers in a first step of a method for receiving,expanding, holding, and placing the staple in a bone, where the stapleis received in a cavity at the tip portion of the pliers;

FIG. 24b shows a partial transparent view of the tip portion of thepliers of FIG. 24a to show details of a toggle lever of the pliers;

FIG. 24c shows a partial transparent view from the side of the tipportion of the pliers of FIG. 24 a;

FIG. 24d shows a plan view of the tip portion of the pliers, including abottom handle, a toggle joint, and the cavity at the tip portion of thepliers;

FIG. 25a shows an enlarged perspective view of the staple and the tipportion of the pliers in a second step of the method for receiving,expanding, holding, and placing the staple in the bone, where the stapleis expanded and held in the cavity at the tip portion of the pliers;

FIG. 25b shows a partial transparent view of the tip portion of theplier of FIG. 25a to show details of the toggle lever of the pliers;

FIG. 25c shows a partial transparent view from the side of the tipportion of the pliers of FIG. 25 a;

FIG. 25d shows a plan view of the tip portion of the pliers, includingthe bottom handle, the toggle joint, and the cavity at the tip portionof the pliers;

FIG. 26 is a schematic drawing showing a distribution of compressionforces along a leg of a staple in an expanded state or when the stapleis just released by an instrument after the staple is inserted intobone;

FIG. 27 shows a perspective view of a surgical staple according to atwelfth embodiment in an expanded state;

FIG. 28a shows an enlarged perspective view of a portion of a first legof the staple of FIG. 27; and

FIG. 28b shows an enlarged perspective view of a portion of a second legof the staple of FIG. 27.

DETAILED DESCRIPTION

A first embodiment of a surgical staple 1 is explained with reference toFIGS. 1a-1d . The staple 1 can be used, for example, with embodiments ofan expansion device 1002 and a staple holder 1090 shown in FIGS. 2a to4, described in greater detail below. FIGS. 1a and 1c show the surgicalstaple 1 in a relaxed state in perspective and front views,respectively. A relaxed state is defined herein as a state in which noexternal forces act on the staple. In cases where the staple is at leastpartially made from shape memory materials, the relaxed state furtherrefers to an austenite phase state, corresponding to a shape of thestaple that is memorized at fabrication.

The surgical staple 1 includes a bridge 2, and a first leg 3 and asecond leg 4 connected to the bridge 2 at respective end sections 29,29′. The bridge 2 includes an elongate body extending between andincluding end sections 29, 29′. The bridge 2 has a rectangular crosssection, thereby forming a top surface 21, front and back side surfaces22, 23 and a bottom surface 24. In the relaxed state shown in FIGS. 1aand 1c , the bridge 2 is arc-shaped or curved. The curvature, or radiusof curvature, is constant in the embodiment shown, but may also varyalong the length of the bridge, or may be present only in portionsthereof. One example of a staple with a bridge having a variablecurvature will be explained below with reference to FIGS. 18a -18 d.

The legs 3 and 4 extend from the end sections 29, 29′ at angles α ofabout 90° with respect to the bridge 2 at the location of theconnections, as can be seen in FIG. 1c . The bottom surface 24 of thearc-shaped bridge 2 forms a curved plane 81′ in the relaxed state, andthe angles a may for example be measured at intersections of lines orplanes 80 extending along lateral surfaces 30, 40 of legs 3, 4,respectively, with curved plane 81′, as illustrated in FIG. 1c . As willbe described in more detail below, angles a do not vary substantiallywhen the staple 1 changes from the relaxed state to an expanded state.

In this first embodiment, as depicted in FIGS. 1a-1d , the end sections29, 29′ of the bridge 2 include extension portions 5, 5′ which extendoutwards beyond the locations of the connections between the bridge 2and the legs 3, 4, respectively. The extension portions 5, 5′ are bothtapered and extend outwards away from the legs in a direction towardsrespective rounded tips, thereby forming slightly inclined surfaceswhich may be engaged by corresponding engagement structures of anexternal tool, in order to expand, or to maintain an expansion of, thesurgical staple 1, as will be described below. More specifically, theextensions 5, 5′ each forms an engagement portion 51, 52, which may bereceived, for example, in a form-fit manner by an external instrument ortool.

The legs 3 and 4 of the surgical staple 1 have outer lateral sidesurfaces 30 and 40, inner side surfaces 70, and front/back side surfaces31 and 41, respectively. Each leg 3, 4 also has a rectangular crosssection. At the inner side surfaces of each leg 3, 4, a number of barbs7 are formed, each of which has a slightly inclined wall 71 and aperpendicularly protruding wall 72, forming a sharp edge. The barbs 7are directed upwardly and serve to improve anchoring in the bone. Anupper portion of the legs 3, 4 adjacent the bottom surface 24 of thebridge 2 may be left free of barbs 7. In this specific embodiment, threebarbs 7 are formed at the inner surfaces 70 of the legs 3 and 4, butmore or less barbs, or even no barbs, may be formed in otherembodiments. Moreover, each of the legs 3, 4 has a tip 6, 6′,respectively. In this embodiment, tips 6, 6′ are flat surfaces whichhave overall square-like cross sections. However, it is also possiblethat the tips 6, 6′ are tapered, sharp, rounded, and/or conicallyshaped, as known in the art, in order to improve the insertion of thelegs 3, 4 into bones. This pertains also to the other embodimentsdescribed below.

The legs 3 and 4 extend substantially perpendicularly from the bridge 2as noted above. As the bridge 2 is arc-shaped in the relaxed state, thelegs 3 and 4 consequently extend towards each other. In this specificembodiment, lines or planes 80 extending along the outer lateral sidewalls 30, 40 of the legs, 3, 4, respectively, intersect each other atabout 30° when the staple 1 is in the relaxed state. However, otherintersection angles ϑ between 25° and 35°, or between 20° and 40°, oreven angles beyond these values, are encompassed as well.

FIGS. 1b and 1d show an expanded state of the surgical staple 1 of thefirst embodiment. In the expanded state, the legs 3 and 4 are movedlaterally away from each other, such as to be arranged in parallel withrespect to each other. The expansion from the relaxed state to theexpanded state is accomplished by applying mechanical energy, forexample, to the bridge 2 via engaging portions 51, 52, wherein thebridge 2 may be bent like a spring. Such expansion can be performed onthe staple 1 when the staple 1 is made of or includes conventionalmaterials such as stainless steel. Such expansion can also be performedon the staple 1 when the staple 1 is made of or includes a shape memorymaterial such as Nitinol. However, the range of deformation can beextended in such staples due to the superelasticity of the material.

Alternatively, when the staple 1 is made of or includes a shape memorymaterial such as, for example, Nitinol, the expansion may also beaccomplished by first cooling the staple 1 to effect the elasticdeformation while the staple 1 is in the martensitic phase. The staplethen exerts its full compression onto the bones after insertion, whenthe staple is again at a higher temperature (e.g., body temperature).

As can be seen particularly in FIG. 1d , the angles a that the legs 3, 4form with the bridge 2 are maintained at 90° when the surgical staple 1is in the expanded state. Therefore, when the legs 3, 4 are madeparallel, the bridge 2 attains a straight shape, and its bottom surface24 becomes substantially flat. The bottom surface 24 thus defines astraight plane 81 that is perpendicular to a plane defined by the bridge2 and the legs 3 and 4.

In the expanded state shown in FIGS. 1b and 1d , the inclined surfacesof the engagement portions 51 and 52 remain above the plane 81 definedby the bottom surface 24 of the bridge 2, which may also correspond witha bone surface when the staple is implanted in or attached to bone(s).That is, when the surgical staple 1 is attached to bone, with the legs 3and 4 inserted, for example, into holes drilled in the bone or bonefragments in advance, the staple 1 may be inserted until the bottomsurface 24 of the bridge abuts on the bone surface, since the engagementportions 51 and 52, and consequently a tool attached to the engagementportions 51, 52, may remain positioned and be engaged or disengagedabove the bone surface.

An embodiment of a device 1002 for expanding the surgical staple 1 isdisplayed in FIG. 2a . The expansion device 1002 is non-limiting, andother devices may be used to effect expansion of the surgical staple 1.The expansion device 1002 has a substantially plate-shaped body 1001,and a boss 1020, which protrudes from and is removably connected to thebody 1001. A first portion 1023 of the boss 1020 adjacent a free end ofthe boss 1020 is arranged to receive the surgical staple 1 in a relaxedstate 1101 (see FIG. 4). An upper surface 1021 of the boss 1020 isdesigned to contact the bridge 2, and more specifically, the bottomsurface 24 thereof. Consequently, at the first portion 1023, the uppersurface 1021 has a curvature corresponding to the arc-shape of thebottom surface 24 of the staple 1 or the curved plane 81′ as shown inFIG. 1b . The legs 3 and 4, which extend towards each other in therelaxed state, are received in recesses 1022 formed on lateral faces ofthe boss 1020 below the upper surface 1021.

The boss 1020 also has a second portion 1024 adjacent to theplate-shaped body 1001. At the second portion 1024, the upper surface1021 is almost flat, corresponding to the flatness of plane 81 of thebottom surface 24 when the staple 1 is in the expanded state, asdepicted by reference 1102 in the enlarged view of FIG. 4. Also, in thesecond portion 1024 of the boss 1020, the depth of recesses 1022 forreceiving the legs 3, 4 is decreased.

Between the first portion 1023 and the second portion 1024 of the boss1020, there is a transfer portion 1025, where the profile of the uppersurface 1021 changes or transitions smoothly from more curved to moreflat, and where the depth of the recesses 1022 transitions smoothly fromdeeper to shallower. Hence, transfer portion 1025 allows for continuousexpansion of the staple 1 by (a) attaching the staple to the boss 1020at the first portion 1023, (b) displacing the staple 1 along thetransfer portion 1025, and (c) disposing or transferring of the staple 1at the second portion 1024 adjacent the plate-shaped body 1001, forexample, to a staple holder 1090, as described below.

The plate-shaped body 1001 is provided with guide walls 1004 and anabutment wall 1005, which form an accommodation space 1003 foraccommodating the staple holder 1090 shown in FIGS. 3a and 3 b.

The staple holder 1090 has a flat, substantially rectangularplate-shaped body 1099 with opposite flat faces 1091, narrow side faces1095, and narrow front faces 1094. Narrow side faces 1095 each has arecess 1092 configured to allow safe manual handling of the stapleholder 1090. The narrow front faces 1094 respectively include apertures1086 allowing access to cavities 1096 formed adjacent to the front faces1094. The cavities 1096 are configured (i.e., shaped, sized, anddimensioned) to receive, for example, the bridge 2 of the staple 1 shownwith respect to the first embodiment.

Moreover, the cavities 1096 are formed with engagement structures 1081,which are respectively provided at ends of cavity 1096, corresponding tothe locations of the engagement portions 51, 52 of the bridge 2 when thebridge 2 is received therein. The engagement structures 1081 are in thisembodiment small projections that project below the engagement portions51, 52 of the bridge 2 when the staple 1 is held in its expanded statein the cavity 1096. Therefore, when the staple holder 1090 is positionedin the accommodation space 1003 of the expansion device 1002 and thestaple 1 reaches the second portion 1024 of the boss 1020 while in theexpanded state, the staple 1 is inserted into the cavity 1096 of thestaple holder 1090, and the engagement portions 51 and 52 are engaged bythe engagement structures 1081 to hold the staple 1 in the expandedstate, as depicted by reference 1102 in FIG. 4. A counterforce isexerted onto the top surface 21 of the bridge 2, particularly in acenter portion thereof, and may for example be provided by an inner backwall 1084 opposite the aperture 1086 of the cavity, which can serve as apressing portion.

As shown in FIG. 4, the accommodation space 1003 provided by guide andabutment walls 1004 and 1005 allows accommodating the staple holder1090. A second aperture 1083 formed in one of the flat faces 1091adjacent to the front face 1094 allows for inserting of the bridge 2when the staple 1 is moved to the second portion 1024 of the boss 1020.When the bridge 2 is at the second portion 1024, with the legs 3, 4abutting against the plate-shaped body 1001 of the expansion device1002, the bridge 2 will also abut against a side wall 1085 opposite theaperture 1083 of the cavity 1096.

When the bridge 2 of the staple 1 is received in one of the cavities1096, the boss 1020 can be removed from the body 1001, and the stapleholder 1090 may be removed from the expansion device 1002, with thesurgical staple 1 held in the expanded state by virtue of the engagementbetween engagement structures 1081 and engagement portion 51, 52,respectively, and further by virtue of a pressing force exerted bypressing portion 1084 urging the bridge 2 of the staple 1 in a directionopposite to the pulling force of the engagement structures 1081.

Next, the surgical staple 1 may be attached to a bone or bone assembly,for example, with holes pre-drilled therein (not shown in thisembodiment). Since the legs 3, 4 are held by the staple holder 1090 inparallel, manual insertion of the staple 1 is facilitated until thebridge 2 abuts on the bone surface. In a next step, the staple holder1090 may release the bridge 2 by moving the staple holder 1090 laterallyrelative to the staple 1, wherein the bridge 2, already adhering to thebone surface, leaves the cavity 1096 of the staple holder 1090 throughthe lateral second aperture 1083. As a consequence, after the bridge 2is released, the staple 1 tries to return into its original curved shapein view of the mechanical energy stored therein, whereby a compressionforce is exerted by the legs 3, 4 on the engaged bones or bone fragmentsto compress the bones or bone fragments together.

Advantageously, no further hammering-in of the staple 1 is necessaryafter the staple 1 is released from the staple holder 1090, according tothis embodiment and to the other embodiments described below. As aconsequence, damage to the bone structure inside the pre-drilled holesin the region of the teeth may be avoided.

A further advantage of this and also of the other embodiments describedherein is that, since the mechanical energy is stored in the bridge 2when it is held at a straight shape, a distribution of the compressionforce of the legs 3, 4 towards each other along the legs 3, 4 is morebroadly distributed, and thus improved. Furthermore, the compressionforce may have a maximum in a region of the first and second barbs 7closest to the bridge 2. Moreover, the compression forces aredistributed farther away from the bridge 2. For example, referring toFIG. 8h , where a staple has been inserted into holes 1351 of bone 1350,compression forces from the legs 3, 4 act upon inner walls 1352 at adeeper position of the holes 1351. Hence, the reliability of theanchoring is also considerably improved.

An impression of the distribution of compression forces exerted by theleg 3 of the surgical staple 1 is further provided in FIG. 26 as anexample. The surgical staple 1 is placed in a pre-drilled hole 1351formed in the bone 1350. The arrows indicate the amount of force exertedby respective portions of the leg 3 on the inner wall 1352 of the hole1351 at various height levels, the forces being oriented in a directionparallel to the bridge 2 and perpendicular to the legs 3, 4, when thesurgical staple 1 is in the expanded state or when the staple 1 has justbeen released.

As can be seen from FIG. 26, a maximum compression force is exerted atabout a height level of the first barb 7 a, or between the first barb 7a and the second barb 7 b, while a smooth distribution of forces down tothe tip 6, 6′ of the leg 3 is achieved. According to the embodimentsdisclosed herein, a smooth maximum compressive force is achieved in amiddle third or even in a bottom third of the legs of the staples.Meanwhile, in the known art, compressive forces exhibit a sharper peakat a height level of the legs that is closer to an upper surface of thebone, or closer to the bridge of the staple, in an upper third of thelegs.

Still further, by storing the mechanical energy within and along thebridge, stress and strain may particularly be reduced at one of the mostcritical regions of the staple, the inner corner at the junction orconnection between each of the legs 3, 4 and the bridge 2. This mayfurther improve the reliability of the staple.

The above described advantages also apply to each of the otherembodiments described below. One particular advantage of the first (andsecond) embodiment of the surgical staple is that, because theengagement portions are formed as extensions 5, 5′ on an outside of legs3, 4, the moment of torque for bending the bridge 2 is considerablyincreased, as compared to cases where, for example, portions of thebottom surface 24 of the bridge 2 adjacent the legs 3, 4 is engaged forexpanding the staple 1. This, in turn, relaxes the requirements for theexternal instrument to maintain the expanded state of the staple 1.

In the above description the staple holder 1090, along with theexpansion device 1002, forms a first embodiment of an expansioninstrument.

As shown in FIGS. 5a-7b , a second embodiment of an instrument in theform of pliers 1202 is shown. The pliers 1202 can be used in conjunctionwith staple 1 of the first embodiment, as well as with other staples(e.g., staples 101 and 901, the embodiments of which are described ingreater detail below). In this embodiment, the staple holder 1090 can bein conjunction with the pliers 1202 to receive and hold the staple 1. Inthe drawings of FIGS. 5a-7b , walls 1092 and 1085 of the staple holder1090 are omitted for simplicity. The pliers 1202 include two handles1204, 1206 rotatably coupled via shaft 1209. Each handle 1204, 1206 hasa tip portion 1205, 1207, respectively. As shown in more detail in FIG.7a , in a first position of the pliers 1202, where the handles 1202,1204 are opened, the tip portions 1205, 1207 are correspondingly closed,such that legs 3, 4 of the staple may be received on an outer sidethereof when the staple 1 is in the relaxed state. Moving the handles1204, 1206 towards one another, to a second position of the pliers 1202,causes the tip portions 1205, 1207 to move away from each other, tosplay the legs 3, 4 of the surgical staple 1 apart, as shown in FIG. 7b.

In this expanded state, the bridge 2 of the staple 1 can the be insertedinto the cavity 1096 of the staple holder 1090, with the legs 3, 4protruding from the staple holder 1090. The pliers 1202, which can bemanually held under tension during this insertion step, may then bereleased. As a consequence, the engaging portions 51, 52 of the surgicalstaple 1 are forcibly engaged by the engaging structures 1081 of thestaple holder 1090, and a pressing force is exerted by the pressingportion 1084 of the back wall of the cavity 1096. The pliers 1202 maythen be removed or disengaged from the staple 1, and the surgical staple1 can be placed in a bone using the staple holder 1090, similarly asdescribed above.

A third embodiment of an instrument and a method of using the instrumentis described with reference to FIGS. 8a-8h . In this embodiment, thetasks of expanding and holding the staple 1 are performed by one singledevice, which is different from the expansion instruments according tothe first and second embodiments.

FIG. 8a shows a step of providing the surgical staple 1. Instrument 1302may also be used in conjunction with other staples, for example, withstaples 101 and 901 described in detail below.

FIG. 8b shows a step of engaging the surgical staple 1 with the thirdembodiment of the instrument, in the form of a pliers-type instrument1302. The bridge 2, including the engaging portions 51, 52, of thestaple 1 is received between engagement structures 1381 provided at tipsof handles or arms 1304, 1306 of the instrument 1302. The handles orarms 1304, 1306, have interfaces 1305, 1307, respectively, for example,for connecting further plier mechanics or components (not shown) toallow suitable actuation of the arms 1304, 1306 by a manual input. Suchmechanics are well-known in the field of pliers and serve to provide asuitable cooperating movement of the arms 1304, 1306.

FIG. 8c shows a step of the method, wherein the surgical staple 1 isexpanded by moving the arms 1304, 1306 of the instrument 1302 towardsone another, thereby pulling the engaging portions 51, 52 upwards, whilepressing portions 1382 at the tip portions of the arms 1304, 1306, pressa center portion of the top surface 21 of the bridge 2 downwards. Inthis state, a cavity is dynamically formed by the instrument 1302 bymeans of engagement structures 1381 and pressing portions 1382, whichwork together to hold the bridge 2 in a straight configuration andstaple 1 in an expanded state.

FIG. 8d illustrates a step of applying the expanded surgical staple 1 tobone, for example, to treat a situation of hallux valgus, or a bunion.In this specific, non-limiting example, an AKIN procedure involving asurgical correction of a misalignment of the first metatarsal isperformed via osteotomy. The surgical staple 1 is applied to openings1353, 1354, for holes 1351 that may have been previously drilled intothe fragments of the bone 1350 (the first metatarsal in this example).The legs 3, 4 of the staple 1 are then aligned with openings 1353, 1354,respectively, using the instrument 1302.

FIG. 8e shows a step of the method wherein the legs 3, 4 are fullyinserted into the holes 1351 using the instrument 1302. The bottomsurface 24 of the bridge 2 has engaged the bone surface, while theengagement structures 1381 of the instrument 1302 are still in forcibleengagement with the bridge 2.

FIG. 8f shows a perspective view of the step depicted in FIG. 8e ,wherein the legs 3, 4 are in the holes 1351, and are still parallel toeach other while the staple 1 is held in the expanded state by theinstrument 1302.

FIG. 8g shows a side view of the step depicted in FIGS. 8e and 8f . Thelegs 3, 4 have not yet engaged the side walls 1352 of the holes 1351, sothe staple is thus not yet anchored in the bone 1350.

FIG. 8h shows a further step of the method of implanting the staple 1using the instrument 1302. The bridge 2 has been released by theinstrument 1302. Therefore, no direct forces act on the bridge 2 to holdthe staple 1 in the expanded state any more. Hence, the staple 1 beginsreverting to the relaxed state and the bridge 2 starts to return back tothe arc-shape. Occasionally, the legs 3, 4 abut on the mutually oppositeside wall surfaces 1352 of the holes 1351, thereby compressing or urgingthe two bone fragments of bone 1350 towards one another. Anchoring ofthe staple 1 in the bone 1350 is also accomplished by the barbs 7 bitingor digging into the bony side wall surfaces 1352 of the holes 1351.

A surgical staple 101 according to a second embodiment, which is amodification of the staple 1 above, will now be described with referenceto FIGS. 9a-9d . Same or similar features to the staple 1 are denotedwith the same reference numerals, and descriptions thereof will not berepeated.

The staple 101 of the second embodiment differs from the staple 1 of thefirst embodiment in that the legs 103, 104 extend from the bridge 2 atangles β and γ, respectively, both of which are different from 90°. Thelegs 103, 104 therefore do not extend perpendicularly from end sections29, 29′ of the bridge 2, but rather at oblique angles. Both anglesdiffer from 90° by about 15°, and the inclinations are oriented towardsthe same direction (e.g., in FIGS. 9a-9d , the legs 103, 104 areinclined towards the left). As a consequence, as can be seen in FIGS. 9band 9d , when the staple 101 is in the expanded state, both legs 103,104 are inclined with respect to the bridge 2, while still extendingparallel to each other.

The embodiment becomes particularly advantageous in clinical situationswhere an inclined insertion of the surgical staple is necessary.

Further embodiments described differ from the first and secondembodiments in that the engagement portions, while still being providedin or adjacent to the end sections 29, 29′ of the bridge, are insteadarranged on the side wall surfaces of the respective bridges. Same orsimilar features to those described in the first embodiment are denotedwith the same reference numerals, and descriptions thereof will not berepeated.

For example, a third embodiment of a surgical staple 301 is depicted inFIGS. 10a-10d . In this embodiment, a bridge 302 is provided which has atop surface 321, a front side wall surface 322, a back side wall surface323, and a bottom surface 324, where the orientation terms are only usedfor reference. As in the first and second embodiments, the bridge 302 ofsurgical staple 301 is arc-shaped or curved in the relaxed state shownin FIGS. 10a and 10c , and is straight or plane-shaped in the expandedstate shown in the FIGS. 10b and 10d . The legs 3, 4 are arrangedsimilarly to the staple 1 in the first embodiment. Upper ends of thelegs 3, 4 adjacent the bridge 302 are slightly reinforced by inclinedouter surfaces 331.

Protrusions that are flush with the top surface 321 are provided at bothside wall surfaces 322, 323 of the bridge 302. Each of the protrusionsextends from the first end section 29 to the second end section 29′. Theprotrusions represent engagement portions 351, 352, which respectivelyform overhangs at the side wall surfaces 322, 323 that are oriented andnarrow towards the legs 3, 4, and which serve to receive a pulling forcefrom engagement structures of an external instrument (not shown) to holdthe staple 301 in an expanded state. The bridge 302 thus has a T-shapecross-section along almost its entire length.

The protrusions of the engagement portions 351, 352 extend up to the endsections 29, 29′, such that an external instrument can apply thenecessary moments of torque to maintain or hold the surgical staple 301in the expanded state. For example, the staple holder 1090 of FIGS. 3a,3b may be modified to include a cavity having engagement structurescomplementary in shape to the protrusions on staple 301. As was seen inthe first and second embodiments, the engagement portions 351, 352 arelocated above a plane 81 when the staple 301 is in the expanded state,which allows removal of the external instrument from the staple 301 evenwhen the staple 301 has been fully inserted in bone.

It should be noted that while the engagement portions 351, 352 extendfrom one end section 29 to the other end section 29′, engagement byengagement structures of an external instrument may occur only in partsthereof, preferably at or adjacent the end sections 29, 29′, asindicated above.

Accordingly, for a surgical staple 601 according to a fourth embodiment,shown with respect to FIGS. 11a-11d , engagement portions 651, 652 maybe provided to extend along side wall surfaces 622, 623 only at oraround end sections 29, 29′. Hence, the T-shape of bridge 602 for staple601 is also provided only at or around the end sections 29, 29′ of thebridge 602.

A fourth embodiment of an instrument 1402, illustrated with respect toFIGS. 12a-12c , may be used in conjunction with the fourth embodiment ofthe surgical staple 601. FIG. 12a shows the surgical staple 601 in arelaxed state, while FIG. 12b shows the instrument 1406 attached to thestaple 601 in the relaxed state. The instrument 1402 may be, for examplea pliers-type instrument, such as spreading pliers, or another device.The instrument 1402 may have arms or handles 1404, 1406 that are similarto the arms 1304, 1306 of the instrument 1302 in FIGS. 8b -8 g.

The arms or handles 1404, 1406 have engagement structures 1481 extendingfrom tip portions of the arms 1404, 1406, that extend outwardly from acentral portion of the bridge 602 to engage around or under theengagement portions 651, 652 of the bridge 602. The handles or arms1404, 1406 can then be moved towards one another for the tip portions torotate relative to one another, as shown in FIG. 12c , thereby liftingor pulling the engagement portions 651, 652 with the engagementstructures 1481. At the same time, flat pressing portions 1482 alsoprovided at the tip portions of the arms or handles 1404, 1406 pressonto the top surface 621 of the bridge 602, which results in anexpansion of the staple 601. The further steps may then be the same asor similar to those explained with regard to FIGS. 8d -8 h.

A fifth embodiment of a surgical staple 701 is shown in FIGS. 13a-13d .The surgical staple 701 differs from the staples 301 and 601 in that oneside wall surface 722 of the bridge 702 has two projectionscorresponding to engagement portions 751, 752 provided only at the endsections 29, 29′, while the other side wall surface 723 has onecontinuous projection corresponding to an engagement portion 753 thatextends fully from one end section 29 to the other end section 29′.

A sixth embodiment of a surgical staple is depicted in FIGS. 14a-14d .In this embodiment, a bridge 202 is provided which has a top surface221, a front wall surface 222, a back wall surface 223, and a bottomsurface 224 where the orientation terms are used only for reference. Asin the previous embodiments, the bridge 202 of surgical staple 201 isarc-shaped or curved in a relaxed state, as shown in FIGS. 14a and 14c ,and is straight or plane-shaped in an expanded state, as shown in theFIGS. 14b and 14d . The legs 3, 4 are similar to legs 3, 4 of the staple1 in the first embodiment. Upper ends of the legs 3, 4 adjacent to thebridge 202 are slightly reinforced by inclined outer surfaces 231.

A protrusion that is flush with the top surface 221 is provided only atthe back wall surface 223, and extends along the back wall surface 223from the first end section 29 to the second end section 29′. Similarlyas seen in previous embodiments, the protrusion 253 forms an engagementportion 251, which may be engaged by an engagement structure of anexternal instrument (not shown) to hold the surgical staple 201 in theexpanded state. The cross section of the bridge 202 of the staple 201according to this embodiment is L-shaped.

The advantages and effects achieved by the sixth embodiment are alsosimilar to those of the staples in the third to fifth embodiments. Thesurfaces of engagement portions 251 are oriented to, or face, the legs3, 4, and are located above a plane 81 defined by the bottom surface 224of the bridge 202 when the staple 201 is in the expanded state.

A seventh embodiment of a surgical staple 801 is shown in FIGS. 15a-15d. The surgical staple 801 is a simple modification of the staple 201shown in the sixth embodiment, wherein the projection extends only at oraround the end sections 29, 29′ to yield single-sided engagementportions 851, 852, which extend along the side wall surface 822 only ina limited region.

A surgical staple 401 according to an eighth embodiment will bedescribed with reference to FIGS. 16a-16b , where the surgical staple401 is shown only in an expanded state. A relaxed state of the staple401 (not shown) is analogous or similar to the relaxed states of thestaples in the previous embodiments. The staple 401 is similar to thestaple 301 according to the third embodiment, in that two continuousprotrusions are respectively formed at side wall surfaces 422, 423 ofbridge 402, and are flush with the top surface 421. However, differentfrom the staple 301 in the third embodiment, the protrusions on staple401 include slightly oblique surfaces, which are only slightly inclinedand narrow towards the legs 3, 4. These oblique surfaces extend alongthe bridge 402 from the first end section 29 to the second end section29′ and are located above the plane 81 defined by the bottom surface 424of the bridge 402 when the staple 401 is in an expanded state. Theprotrusions and oblique surfaces form engagement portions 451, 452,which may be engaged by corresponding engagement structures of anexternal instrument (not shown), to maintain or hold the staple 401 inthe expanded state prior to and during implantation of the staple 401.

A ninth embodiment will be described with reference to FIGS. 17a-17b ,which shows a surgical staple 501, also only in an expanded state. Arelaxed state of staple 501 (not shown) is analogous or similar to therelaxed states of the staples in the previous embodiments. For staple501, side wall surfaces 522 and 523 of bridge 502 include recessesextending from the first end section 29 to the second end section 29′ ata central height level of the side wall surfaces 522, where the recessesare also above a plane 81 defined by bottom surface 524 of the bridge502 when the staple 501 is in an expanded state. The recesses haveconcave cross sections and form engagement portions 551, 552 to beengaged by engagement structures of an external instrument (not shown),for maintaining or holding the surgical staple 501 in the expandedstate. Since the recesses reduce the thickness of the bridge 502, theoverall layout of the bridge 502 can be provided with a correspondinglylarger thickness to comply with stability requirements of the surgicalstaple 501.

This staple embodiment provides an advantageous alternative to thepreviously described staples, since corresponding engagement structuresof an external instrument may have a complementary shape, for example,elongate convex protrusions, and no further contact with the top surface521 of the bridge 502 may be necessary to maintain or hold the staple501 in the expanded state. This embodiment may therefore be particularlyuseful when pliers or the like are used as the external instrument tohold and implant the staple.

Several other modifications may also be made with regard to the aboveembodiments.

For example, in the above embodiments, the cross section of the bridgeand the legs for some of the staple embodiments was described to berectangular. Alternatively, the cross sections may be, for example,circular, oval, or polygonal, and may include, for example, rounded orchamfered edges.

In addition, in the above embodiments, when the staples are in a relaxedstate, the arc-shapes of the bridges of the staples were generallydescribed to be continuous and smooth. However, it is also possible thatonly portions of the bridge are curved or bended. A tenth embodiment ofa surgical staple 901 is illustrated in FIGS. 18a-18d . The bridge 902includes two bending portions 909 which connect straight portions of thebridge 902. The bending portions 909 are provided adjacent to or on bothsides of a center portion of the bridge 902, but not at the end sections29, 29′. The surgical staple has projecting extensions 5, 5′ formingengagement portions 951, 952, such that the same or similar advantagesand effects described with regard to the first embodiment of thesurgical staple 1 may also be achieved here.

Moreover, in the above embodiments, Nitinol was described as one of thematerials from which the surgical staple is made, or at least partiallymade. Alternatively, in embodiments where staples include shape memory,any suitable shape memory material may be employed. Also, non-shapememory materials are encompassed by the invention. Further examples arebiocompatible materials including stainless steel, titanium,beta-titanium alloys including molybdenum, vanadium, niobium, tantalum,zirconium, manganese, iron, chromium, cobalt, nickel, and copper.Titanium alloys also provide excellent formability and reliability. Inaddition, magnesium based materials, for example, may also be used.

In the above embodiments, the staples include a bridge and two legsgenerally extending within one plane. However, more complexthree-dimensional structures are encompassed as well. Moreover, stapleswith more than two legs may also be used.

Furthermore, in the above embodiments, the bridge of the staple isdescribed to attain a straight flat shape when the staple is in theexpanded state. However, other bridge shapes may also be attained in theexpanded state, when the legs are arranged in parallel and ready forinsertion into bone.

In the above third embodiment for example, a surgical staple 301including engagement portions 351, 352 formed as projections extendingalong the outer side wall surfaces 322, 323 is described. Theprojections are formed such as to extend above a plane defined by thebottom surface 324 of the bridge 302 when the staple 301 is in theexpanded state. In other words, the engagement portions 351, 352 areentirely distant or spaced apart from the bottom surface 324 in thestaple 302, as well as in staples described with respect to the otherembodiments.

However, in yet another, eleventh, embodiment shown in FIGS. 20a-20d , asurgical staple 2301 has a bridge 2302 including a bottom surface 2324and one or more projections 2354 with engagement portions 2351, 2352,where the bottom surface 2324 and the engagement portions 2351, 2352approach each other at a center portion of the bridge 2302. Bottomsurfaces of the engagement portions 2351, 2352 can assume, for example,a straight shape while the bottom surface 2324 of the bridge 2302 iscurved, when the staple 2301 is in the relaxed state, as seen in FIGS.20a and 20c . Meanwhile, the bottom surfaces of the engagement portions2351, 2352 can assume a convex shape, while the bottom surface 2324 ofthe bridge 2302 straightens, when the staple 2301 is in the expandedstate, as shown in FIGS. 20b and 20 d.

Nevertheless, similarly as explained with respect to the embodiment ofFIG. 12b , for example, the parts of the projections which areconfigured for engagement by an external tool for expansion of thestaple, are in some embodiments, ideally provided at or adjacent the endportions 29, 29′ of the staple, so that sufficient torque can be appliedto the staple for the expansion. In this regard, even in thisembodiment, the outer regions of the engagement portions 2351, 2352 thatengage an external tool may still extend at least partially above aplane defined by a bottom surface 2324 of the bridge 2302 when thestaple is in the expanded state, to achieve safe placement of the staple2301 in bone. As a consequence of the convex arc-shape of the bottomsurface of the projection 2354, the bottom surface is inclined withrespect to the legs 3, 4, as well as with respect to the plane 81defined by the bottom wall surface 2324 of the bridge 2302 when thestaple 2301 is in the expanded state, similarly as described withrespect to the first embodiment.

Meanwhile, in the above instrument embodiments, tip portions provided atarms or handles of various plier-type instruments are described to formcavities for receiving and holding bridges of staples. However, it alsopossible in other tool or instrument embodiments that further parts alsocontribute to the shape of the cavity, for example, as seen in a fifthembodiment of an instrument 1502, explained with respect to method stepsin FIGS. 19a-19c . A surgical staple 1 is provided in FIG. 19a , withengagement portions 51, 52 formed as extensions 5, 5′ of a bridge 2,similarly as seen in FIGS. 1a -1 d.

The instrument 1502, which may be a pliers-type instrument, has handlesor arms 1504, 1506, with tip portions similar to those described withrespect to the embodiments of instruments 1302, 1402 described above.Engagement structures 1581 are provided to engage the engagementportions 51, 52 of the bridge 2, as shown in FIG. 19 b.

For instrument 1502, an additional pressing member 1510 is furtherprovided between arms or handles 1504, 1506. Pressing member 1510 has atapered profile, such that when advanced towards a top surface of thebridge 2, the arms or handles 1504, 1506 may be slightly displaced awayfrom each other. When a pressing portion 1582 at a front end of thepressing member 1510 abuts the top surface of the bridge 2, the bridge 2is bent, and a length between the end sections 29, 29′ or extensions 5,5′ along a horizontal or width direction of the staple 1 increases.

However, as shown in FIG. 19c , when the staple 1 is expanded, the taperof pressing member 1510 also allows the arms 1504, 1506 to also furtherseparate, so that the cavity formed by the arms 1504, 1506 is alsoslightly elongated to form a complementary shape providing a form-fitconnection for the bridge 2.

A sixth embodiment of an instrument in the form of pliers is shown withrespect to FIGS. 21-22 c. The pliers 1602 has arms or handles 1604,1606, which are rotationally coupled to each other. The handles 1604,1606 include tip portions which form a cavity 1696 similarly to themanner described above with respect to other tool or instrumentembodiments. The arms 1604, 1606 have engagement structures 1681projecting from respective ends of the cavity 1696 to engage engagementportions 51, 52 of a surgical staple 1, similar to the staple describedaccording to the first embodiment.

Similar to the fifth embodiment of the instrument, a pressing portion1682 is provided in the cavity by a separate part. Here, the pressingportion 1682 is a surface at a tip portion of a screw member 1610. Asshown in FIG. 21, a threaded bore is provided in one or both of thehandles 1604, 1606 to receive the screw member 1610 therein. FIGS.22a-22c show a process of receiving and expanding the staple 1. First,in FIG. 22a , the handles 1604, 1606 can be brought closer together toexpand the cavity 1696 to receive the bridge 2 of the staple 1,including extensions 5, 5′ and/or engagement portions 51, 52. Here, thescrew member 1610 can be retracted, while the staple 1 is inserted inthe relaxed state, as shown in FIG. 22b . Next, the screw member 1610 isactuated or screwed-in to advance the pressing portion 1682 towards andagainst the top surface 21 of the bridge 2, indicated by the arrows inFIG. 22c . As a consequence, the staple 1 assumes its expanded state,where the bridge 2 is bent into a straight shape and the legs 3, 4 moveaway from each other to assume a parallel orientation. In a next step(not shown), the staple 1 may then be applied to one or more bones.

A seventh embodiment of an instrument, in another form of pliers, isshown with respect to FIGS. 23a-25d . The pliers 1702 has arms orhandles 1704, 1706 which are rotationally coupled to each other. Thehandles 1704, 1706 include tip portions in which a cavity 1796 forholding a staple 1 is formed, similarly to the manner described abovewith respect to the other instrument embodiments.

However, unlike in the previous instrument embodiments, pliers 1702provide for a combined movement of engagement structures 1781 andpressing portion 1782, which together form the cavity 1796 for expandingthe surgical staple 1. The cavity 1796 extends parallel to an axis ofrotation of the handles 1704, 1706 (e.g., see rotational shaft hole 1708in FIG. 23a ), rather than being perpendicular thereto as was the casein previous embodiments. Hence, when opening the handles 1704, 1706 ormoving the handles 1704, 1706 away from one another, the cavity 1796also opens and the staple 1 may be inserted into the cavity 1796 (seeFIGS. 24a-24d ). In this embodiment, the tip portions of handles 1704,1706 include almost identical complementary shapes for forming thecavity 1796. When the handles 1704, 1706 are closed or moved towards oneanother, the cavity 1796 is also closed (see FIGS. 25a-25d ), and thebridge 2 of the surgical staple 1 is safely received in the cavity 1796in a form-fit manner.

Expansion of the surgical staple 1 is effected by means of a togglelever 1720, which is best seen in the partially transparent views of theinstrument in FIGS. 24b and 25b . The toggle lever has two lever arms1721, 1722, which are rotationally coupled at one end to tip portions ofthe handles 1704, 1706 via joints 1723, 1724, respectively. The otherends of both lever arms 1721, 1722 are rotationally coupled to eachother via a joint 1725. Opening and closing the handles 1704, 1706 ofthe pliers 1702 thus also results in retraction and advancement of themutually coupled ends of the lever arms 1721, 1722 to and from thecavity 1796. The mutually coupled ends of lever arms 1721, 1722 therebyform a pressing portion 1782 shaped and positioned to abut on a centerportion of the bridge 2 when the pressing portion 1782 is advanced intothe cavity 1796, in conjunction with a closing movement of the handles1704, 1706, or when the handles 1704, 1706 are moved towards oneanother.

A twelfth embodiment of a surgical staple is explained with reference toFIGS. 27, 28 a, and 28 b. The surgical staple 2101 is similar to thestaple 1 according to the first embodiment in that a bridge 2 has endsections 29, 29′ at which there are provided respective extensions 5,5′, which form engagement portions 51, 52 for engagement by aninstrument. However, this embodiment differs from the previouslydescribed embodiments of surgical staples with regard to the arrangementand geometry of barbs at respective legs 2103, 2104.

More specifically, as shown in FIG. 27, both legs 2103, 2104 areprovided with barbs 2107 a, 2107 b which have a different geometry ortooth profile than the barbs 7 of the first to eleventh embodiments. Inthe previous embodiments, the overall size of the barbs 7 both along thelengths and perpendicular to the lengths of the legs 3, 4 is relativelysmall.

In this embodiment, barbs 2107 a, 2107 b are instead arranged and sizedin view of the specific application of the surgical staple at animplantation site. For example, some bones or parts of bones, such asthe central or diaphysis regions of bones, may generally involve regionswith stiffer bone tissue, for example, where supply of bone tissue withblood is less prominent. In contrast, bone regions located closer tojoints have more soft and spongy bone tissue.

With regard to those regions having more soft bone tissue, for example,near a joint, a profile of teeth or barbs 2107 a, as shown in FIGS. 27and 28 a, may be provided. The barbs 2107 a are more pronounced ascompared with barbs 7 of the previous embodiments. The profile ofadjacently arranged barbs 2107 a resembles, for example, that of sharkteeth. The height or extension of barb edges 2176 away from the leg 2104may be larger as compared with the barbs in previous embodiments. Also,the length of the barbs 2017 a measured along a length of the leg 2104may also be larger, and adjacent barbs 2107 a may continuously mergewith each other at the legs 2104.

A shape of the barbs 2017 a may include a concave shaped surface 2171 asmoothly rising from a bottom of recesses between the barbs 2017 a. Thatsurface 2171 a merges or continues into a convex shaped surface 2173,which in turn merges or continues into a substantially flat surface2174, which may be substantially parallel to a line or plane 80 of theleg 2104. This profile smoothly compresses the adjacent soft bone tissuewhen the staple is driven into the bone and is released from theexpanded state. Flat surface 2174 further forms the sharp edge 2176together with a flat surface 2175, which steeply inclines on the side ofthe cutting surface of the barb 2017 a. Flat surface 2175 defines aplane 2177 which forms an angle with line or plane 80 that is less than90 degrees, for example, 70 to 85 degrees, and more preferably 75 to 80degrees, in order to increase the barb function. The overhanging flatcutting surface 2175 bites or pierces into the adjacent soft bone tissueand improves the holding characteristics of the staple 2101. An angle Aformed at the barb edge between surfaces 2175 and 2176 is also less than90 degrees, for example, 70 to 85 degrees, and more preferably 75 to 80degrees. Concavely rounded surface 2712 a then provides a steeptransition towards the recess between adjacent barbs 2017 a.

It may be noted that surface 2175 may also be slightly rounded, or maybe part of steeply rising rounded surface 2172 a with a similar concavecurvature.

Another barb profile that may be more suited for stiffer tissue regionsis displayed with respect to FIGS. 27 and 28 b. Herein, a height orextension of barb edges 2176 of barbs 2107 b away from the leg 2103 maybe less than the height of barbs 2107 a, such that a bite or piercingdepth of the barbs 2107 b into the stiffer bone tissue may be less.Moreover, the smoothly rising side of each barb 2107 b may have only aconcave shaped surface 2171 b, without any convex shaped portions. Also,on the cutting side of each barb 2107 b, there is a steeply risingrounded surface 2172 b, which forms the barb edge 2176 together withsurface 2171 b. Adjacent the barb edge 2176, a plane or line 2179tangential to steeply rising rounded surface 2712 b forms an angle nwith a line or plane 80 of the leg 2103. In some embodiments, angle nmay be formed to be 90 degrees or greater.

Moreover, surfaces 2171 b and 2172 b form a considerably more slenderprofile for the barb 2107 b, compared with a profile of barb 2107 a. Anangle p formed between tangential planes 2178 and 2179 of respectivesurfaces 2172 b, 2171 b may be about 50 to 80 degrees, and morepreferably 60 to 70 degrees, which may be less than the angle A formedat the barb edge between surfaces 2175 and 2176 of barb 2107 a. In otherwords, barb 2107 b has a profile which is less pronounced, more slender,and oriented in a direction facing away from the leg 2103, as comparedto the relationship between barbs 2107 a and leg 2014.

FIG. 27 depicts a situation where a surgical staple 2101 has legs 2103,2104 provided with different barbs 2107 a, 2017 b. Such a staple may beused, for example, for an osteotomy such as the one shown in FIG. 8d ,with leg 2104 applied closer to a joint and leg 2103 applied fartheraway from the joint. However, alternatively or additionally, as alsoshown in FIG. 27, the number of barbs 2107 a or 2107 b on each leg 2103,2104 may also be varied even within one staple 2101. Still further, thenumber of barbs per unit length may be varied even within one leg, forexample, depending on the expansion forces visualized in FIG. 26. Stillfurther, the profile of each of the barbs on each leg may also be variedor different from one another. For example, the barbs may be arrangedasymmetrically or variably along the length of one leg, or in someembodiments both legs, such that the barbs are longer and/or have alarger profile or geometry near an end of the leg, while being shorterand/or having a smaller profile or geometry near a top of the leg closerto the bridge of the staple, for the staple to better grip the bone whenimplanted.

In contrast, it is also possible to provide one surgical staple withjust one type of barb profile for both legs, without any variation. Itis also possible, for example, to provide each leg with just one barb,or even no barbs, or to provide one leg with one or more barbs and theother leg with no barbs.

Many further modifications of the surgical staple and/or the instrumentsare also possible.

While the present invention has been described in connection withcertain exemplary embodiments, it is to be understood that the inventionis not limited to the disclosed embodiments, but is instead intended tocover various modifications and equivalent arrangements included withinthe spirit and scope of the appended claims, and equivalents thereof.

What is claimed is:
 1. A surgical staple insertion system forcompressing bones or bone fragments, comprising: a) a surgical staple,including: a solid first leg for anchoring in a first bone or bonefragment, a solid second leg for anchoring in a second bone or bonefragment, and an elastically deformable bridge monolithically formedwith the first leg and the second leg, the bridge having a first endsection from which the first leg extends and a second end sectionopposite the first end section from which the second leg extends,wherein in a relaxed configuration, the bridge is bent or curved suchthat a central region of the bridge is directed away from the first andsecond legs, and free ends of the first and second legs are positionedcloser to one another than are portions of the first and second legsconnected to the bridge, and wherein the bridge comprises engagementportions at each of the first and second end sections that extend awayfrom each other and outward from the first and second legs; and b) aninsertion tool including a unitary piece of material having a first endand a second end, the second end defining a cavity configured to receivethe engagement portions at each of the first and second end sections ofthe bridge of the staple such that the bridge is retained in a deformedconfiguration relative to the relaxed configuration with the first andsecond legs retained parallel to each other.
 2. The system of claim 1,wherein the first and second legs include teeth for engaging the bone orbone fragments.
 3. The system of claim 1, wherein in the deformedconfiguration, the bridge has a straight shape.
 4. The system of claim1, wherein when the bridge is in the relaxed configuration, the firstand second legs have respective leg axes that form an angle between 20and 40 degrees relative to each other.
 5. The system of claim 1, whereinthe bridge, the first leg, and the second leg extend in a common planewhen the bridge is in both of the relaxed and deformed configurations.6. The system of claim 1, wherein the surgical staple comprises a shapememory material exhibiting superelastic properties.
 7. The system ofclaim 1, wherein the unitary piece of material is a flat sheet.
 8. Thesystem of claim 7, wherein the bridge, the first leg, and the second legof the staple and the flat sheet all extend in a common plane.
 9. Thesystem of claim 1, wherein the first end of the tool defines a handle tomanipulate the second end of the tool and the staple.
 10. The system ofclaim 1, wherein the insertion tool consists of a unitary piece of sheetmaterial.
 11. A surgical staple insertion system for compressing bonesor bone fragments, comprising: a) a surgical staple, including: a solidfirst leg for anchoring in a first bone or bone fragment, a solid secondleg for anchoring in a second bone or bone fragment, and an elasticallydeformable bridge monolithically formed with the first leg and thesecond leg, the bridge having a first end section from which the firstleg extends and a second end section opposite the first end section fromwhich the second leg extends, wherein in a relaxed configuration, thebridge is bent or curved such that a central region of the bridge isdirected away from the first and second legs, and free ends of the firstand second legs are positioned closer to one another than are portionsof the first and second legs connected to the bridge, and wherein thebridge comprises engagement portions at each of the first and second endsections that extend away from each other and outward from the first andsecond legs; and b) an insertion tool consisting of a unitary piece ofmaterial having a first end and a second end, the second end defining acavity configured to receive the engagement portions at each of thefirst and second end sections of the bridge of the staple such that thebridge is retained in a deformed configuration relative to the relaxedconfiguration with the first and second legs retained parallel to eachother.
 12. The system of claim 11, wherein the unitary piece of materialis a flat sheet material.
 13. A method of inserting a staple into a boneor bone fragments, comprising: a) providing a surgical staple mounted onan insertion tool, (i) the surgical staple including, a solid first legfor anchoring in a first bone or bone fragment, a solid second leg foranchoring in a second bone or bone fragment, and a bridge monolithicallyformed with the first leg and the second leg, the bridge having an uppersurface, a lower surface, a central portion, a first end section fromwhich the first leg extends and a second end section opposite the firstend section from which the second leg extends, wherein the bridgecomprises engagement portions at each of the first and second endsections that extend away from each other and outward from the first andsecond legs, the bridge having a relaxed configuration in which thebridge bends or curves so that a central region of the bridge isdirected away from the first and second legs, and free ends of the firstand second legs are positioned closer to one another than are portionsof the first and second legs connected to the bridge, and (ii) theinsertion tool provided separately and distinctly formed from the stapleand having a first end and a second end, the second end defining acavity in which the engagement portions at each of the first and secondend sections of the bridge and a portion of the bridge between the firstand second end sections are held in an elastically deformedconfiguration in which energy is stored in the bridge and the first andsecond legs retained parallel to each other; b) holding the insertiontool and directing the parallel first and second legs of the stapletoward the bone or bone fragments; c) applying sufficient force to pushthe parallel first and second legs of the staple into the bone or bonefragments; and d) releasing the insertion tool from over the bridge ofthe staple such that the stored energy biases the bone or bone fragmentsbetween the first and second legs toward each other.
 14. The method ofclaim 13, wherein the provided insertion tool is a unitary, flat sheetmaterial.
 15. The method of claim 13, wherein providing the staplemounted on the insertion tool includes elastically deforming the bridgeof the staple, inserting the bridge of the staple into the cavity of theinsertion tool such that the engagement portions and upper surface areretained in contact with peripheral surfaces of the cavity.
 16. Themethod of claim 13, wherein providing the staple mounted on theinsertion tool includes elastically deforming the bridge of the staple,inserting the bridge of the staple into the cavity of the insertion toolsuch that the engagement portions and central portion of the bridge areretained in contact with peripheral surfaces of the cavity.
 17. Themethod of claim 13, wherein releasing includes moving at least a portionof the insertion tool laterally relative to the bridge of the staple.